Switch SupportsUserData uses to use unique_ptr.

ios/web/web_state/ui/wk_web_view_configuration_provider.h

Index: ios/web/web_state/ui/wk_web_view_configuration_provider.h
diff --git a/ios/web/web_state/ui/wk_web_view_configuration_provider.h b/ios/web/web_state/ui/wk_web_view_configuration_provider.h
index d85ad22d36c4685fc399eddbd2725da8508d6b9a..dd8de96942cf58b4ecafaadfed30c24c14b7c919 100644
--- a/ios/web/web_state/ui/wk_web_view_configuration_provider.h
+++ b/ios/web/web_state/ui/wk_web_view_configuration_provider.h
@@ -22,6 +22,8 @@ class BrowserState;
 // main thread.
 class WKWebViewConfigurationProvider : public base::SupportsUserData::Data {
  public:
+  ~WKWebViewConfigurationProvider() override;
+
   // Returns a provider for the given |browser_state|. Lazily attaches one if it
   // does not exist. |browser_state| can not be null.
   static web::WKWebViewConfigurationProvider& FromBrowserState(
@@ -47,7 +49,6 @@ class WKWebViewConfigurationProvider : public base::SupportsUserData::Data {
  private:
   explicit WKWebViewConfigurationProvider(BrowserState* browser_state);
   WKWebViewConfigurationProvider() = delete;
-  ~WKWebViewConfigurationProvider() override;
 
   base::scoped_nsobject<WKWebViewConfiguration> configuration_;
   base::scoped_nsobject<CRWWKScriptMessageRouter> router_;